Optimization system and method used in uncontrolled rectification sending-out scene of network construction type fan

Abstract

The invention discloses an optimization system and an optimization method used in an uncontrolled rectification sending-out scene of a constructed network type fan, and relates to the technical field of new energy sending-out and power electronics. Compared with a previous converter station, the converter station solves the problems that the construction cost advantage of a sending end platform is difficult to play due to the fact that an existing scheme adopts uncontrolled rectification output, an additional reactive power compensation device needs to be configured, and the size is large; an uncontrolled rectifier bridge is used for sending out, harmonic waves with a large proportion exist, and the electric energy quality of a sending-end power grid is affected; through a mode of combining a PV control algorithm and a Qf control algorithm for connecting uncontrolled rectification power transmission of a grid-forming type fan with an optimization system, the capacitance value of a compensation capacitor is reduced, the cost is saved, the occupied area of a reactive compensation facility is reduced, and the construction cost of a compensation device is saved; and the harmonic voltage and the harmonic capacitance on the converter transformer valve side circuit can be obviously reduced, and the method has application value for practical engineering.

Description

Technical Field

[0001] The present invention relates to the field of new energy transmission and power electronics technology, and in particular to an optimization system and method for a grid-type wind turbine connected to an uncontrolled rectifier transmission scenario. Background Art

[0002] In order to achieve the goal of "dual carbon" as soon as possible, my country will vigorously develop renewable energy, but the existing converter stations have certain disadvantages: MMC (Modular Multilevel Converter, MMC) converter stations occupy a large area, have complex control and high construction costs; LCC converter stations rely on grid phase change, and there is a risk of phase change failure, which will cause large economic losses; two-level and three-level converter stations have high switching frequencies in high-voltage direct current transmission, which have extremely high requirements for power electronic devices and are not easy to implement.

[0003] Although the transmission of wind power through DRU (Diode Rectifier Unit, DRU) can greatly reduce the volume and weight of the converter station at the sending end, the existing scheme still has the following shortcomings: 1. The use of uncontrolled rectifier transmission requires the configuration of additional reactive power compensation devices, which are large in size, making it difficult to play the construction cost advantage of the converter platform at the sending end. 2. The use of uncontrolled rectifier bridge transmission has a large proportion of harmonics, which affects the power quality of the sending-end power grid.

[0004] In order to solve the above problems, the present invention proposes an optimization system and method for a grid-type wind turbine connected to an uncontrolled rectifier and output scenario. Summary of the invention

[0005] The purpose of the present invention is to propose an optimization system and method for a grid-type fan connected to an uncontrolled rectifier and delivery scenario to solve the problems raised in the background technology:

[0006] The existing solution adopts uncontrolled rectifier transmission, which requires the configuration of additional reactive power compensation devices, which are large in size, making it difficult to realize the construction cost advantage of the sending-end commutation platform; it also adopts uncontrolled rectifier bridge transmission, which has a large proportion of harmonics, affecting the power quality of the sending-end power grid.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] An optimization system for a grid-type wind turbine connected to an uncontrolled rectification and transmission scenario, the optimization system comprising: an improved parallel capacitor commutation converter and a system used in a grid-type wind turbine connected to an uncontrolled rectification and transmission scenario, the improved parallel capacitor commutation converter comprising a converter transformer, a filter inductor, a parallel capacitor, and a converter; the system used in the grid-type wind turbine connected to an uncontrolled rectification and transmission scenario comprises a collection system, the collection system being used to collect wind turbines in each wind farm;

[0009] The improved parallel capacitor commutation converter is applied to the diode rectifier converter station DRU. The topological connection of the system applied to the scenario of the DRU converter station and the grid-type wind turbine connected to the uncontrolled rectifier and transmission is as follows:

[0010] The wind turbines in each wind farm are collected to the sending-end collection system through their respective converters and short-distance AC cables. After being stepped up by the step-up transformers, the wind turbines in each wind farm are connected to the nearest sending-end DRU converter station through short-distance cables, and after being rectified by the converter, they are transmitted to the receiving-end modular multi-level converter through long-distance DC cables, and then are inverterized and connected to the industrial frequency AC receiving-end power grid; wherein the sending-end DRU converter stations are connected to each other through short-distance DC connection cables; the collected AC bus first passes through the converter transformer, and then through the series filter inductor and shunt capacitor, and is connected to the AC inlet of the converter, and a smoothing reactor is also connected in series on the DC side; the sending-end DRU converter station is cascaded by m 12-pulse DRUs, wherein each bridge arm of the DRU is composed of a number of diodes connected in series.

[0011] Preferably, the operating frequency of the collection system is 50 Hz;

[0012] The grid-type fan adopts process control, namely PV control and droop control, namely Qf control.

[0013] The optimization method for the scenario of grid-type wind turbine connected to uncontrolled rectifier and output includes the following steps:

[0014] The power operation characteristics of the system used in the scenario of the grid-type wind turbine connected to uncontrolled rectification and transmission are analyzed, and it is found that there is a correlation between active power and the voltage of the sending-end system, and there is a correlation between reactive power and frequency, and there is a gap in reactive power. The reactive power gap in the scenario of the grid-type wind turbine connected to uncontrolled rectification and transmission is filled by the optimization system; the circuit analysis of the optimization system is performed to obtain the reactive compensation expression of the optimization system, and the parameters of the series filter inductor and the shunt capacitor are adjusted according to the reactive compensation expression; and the performance of the optimization system after parameter adjustment is evaluated.

[0015] Preferably, in the system used in the scenario of grid-connected wind turbines connected to uncontrolled rectifiers, an equivalent circuit model of the wind turbine grid-side converter outlet is constructed to obtain the active power and voltage expressions at the wind turbine generator set outlet as follows:

[0016]

[0017] Where: P wt is the active power generated by the fan; V dci is the DC side outlet voltage of the uncontrolled rectifier valve; N is the number of twelve-pulse uncontrolled rectifier bridges in series; E is the AC side voltage of the uncontrolled rectifier valve; X Tis the impedance of the converter transformer;

[0018] The expression of reactive power and frequency at the outlet of wind turbine is:

[0019]

[0020] Where: Q wt V is the reactive power generated by the fan; PCC is the grid voltage at the sending end; V dcr is the DC side voltage of the receiving-end converter; μ is the commutation overlap angle of the uncontrolled rectifier bridge; C0 is the capacitance of the equivalent reactive power compensation device;

[0021] By analyzing the voltage of the sending-end grid, the expression is:

[0022]

[0023] Where: T dr R is the transformer ratio of the uncontrolled rectifier valve converter; dc is the equivalent resistance of the DC transmission line;

[0024] The analysis shows that there is a correlation between the active power generated by the wind turbine and the voltage of the sending-end grid; and the DC voltage at the receiving end has a clamping effect on the voltage of the sending-end grid, limiting the amplitude of the voltage change of the sending-end grid; when the voltage amplitude is fixed, there is a correlation between the frequency at the outlet of the wind turbine and the reactive power, so the wind turbine achieves frequency synchronization through reactive power synchronization control, and achieves output voltage stability of the sending-end wind farm by controlling the active power.

[0025] Preferably, the following analysis is performed based on the equivalent model of the grid-side converter outlet of the optimization system:

[0026]

[0027] in, To optimize the system output current; is the current of the input optimization system; j is the imaginary unit; n is the harmonic number; ω is the angular frequency; k is the bus voltage of the power grid at the sending end; T is the ratio of the converter transformer of the uncontrolled rectifier valve; L is the series filter inductance of the optimization system; C is the filter capacitor of the optimization system; 1∠30° represents the phase angle of the offset;

[0028] Ignoring the harmonic content of the bus voltage, transform the complex frequency of the above formula:

[0029]

[0030] Where G(s) is the transfer function; s is the Laplace complex variable;

[0031] Define the index k n :

[0032]

[0033] Combined, we get:

[0034]

[0035] Among them, k n Indicates the conversion rate of the nth harmonic current after capacitor filtering.

[0036] Preferably, during the application of the optimization system, the control strategies of AC voltage, active power, reactive power and frequency at the sending end during the stable transmission stage of wind power are as follows:

[0037] The voltage of the power grid at the sending end is controlled by the wind turbines, and the d-axis voltage reference value of each wind turbine is generated through active power control. Generate the phase θ of each wind turbine through reactive power synchronization control i , combined with U 0q Reactive current reference value generated by the control link To change Q wt size so that the system reactive power is balanced.

[0038] Preferably, the parameter setting of the series filter inductor and the shunt capacitor is specifically as follows:

[0039] Calculate the active power and reactive power in the AC system as follows:

[0040]

[0041] Among them, P and Q are the active power and reactive power of the AC system respectively; U PCC is the AC bus voltage amplitude; I dc is direct current;

[0042] According to actual engineering needs, set |k n |=m% and the values ​​of active power P and reactive power Q to be adjusted, where m is the setting parameter; and at the same time, the optimal variation range of LC is set.

[0043] The optimization device used in the scenario of grid-type wind turbine connected to uncontrolled rectification and transmission includes:

[0044] Scenario analysis module: used to analyze the power operation characteristics of the grid-type wind turbine connected to the uncontrolled rectifier transmission scenario, and obtain the correlation between active power and the voltage of the sending end system, the correlation between reactive power and frequency, and the existence of reactive power gap;

[0045] Topology optimization module: used to perform topology optimization through the optimization system to fill the reactive power gap in the scenario where the grid-type wind turbine is connected to an uncontrolled rectifier and sent out, and also to perform circuit analysis on the optimization system to obtain a reactive power compensation expression for the system;

[0046] Parameter setting module: used for setting the parameters of the series filter inductor and the shunt capacitor in the system according to the reactive compensation expression;

[0047] Performance evaluation module: used to evaluate the performance of the optimization system after parameter adjustment.

[0048] Preferably, in the scenario analysis module, an equivalent circuit model of the wind turbine grid-side converter outlet is built for the system applied to the scenario of grid-connected wind turbines connected to uncontrolled rectification and transmission, and the active power and voltage expressions of the wind turbine generator set outlet are obtained as follows:

[0049]

[0050] Where: P wt is the active power generated by the fan; V dci is the DC side outlet voltage of the uncontrolled rectifier valve; N is the number of twelve-pulse uncontrolled rectifier bridges in series; E is the AC side voltage of the uncontrolled rectifier valve; X T is the impedance of the converter transformer;

[0051] The expression of reactive power and frequency at the outlet of wind turbine is:

[0052]

[0053] Where: Q wt V is the reactive power generated by the fan; PCC is the grid voltage at the sending end; V dcr is the DC side voltage of the receiving-end converter; μ is the commutation overlap angle of the uncontrolled rectifier bridge; C0 is the capacitance of the equivalent reactive power compensation device;

[0054] By analyzing the voltage of the sending-end grid, the expression is:

[0055]

[0056] Where: T dr R is the transformer ratio of the uncontrolled rectifier valve converter; dc is the equivalent resistance of the DC transmission line;

[0057] The analysis shows that there is a correlation between the active power generated by the wind turbine and the voltage of the power grid at the sending end; and the DC voltage at the receiving end has a clamping effect on the voltage of the power grid at the sending end, limiting the voltage variation of the power grid at the sending end; when the voltage amplitude is fixed, there is a correlation between the frequency and reactive power at the outlet of the wind turbine, so the wind turbine achieves frequency synchronization through reactive power synchronization control, and achieves output voltage stability of the wind farm at the sending end by controlling active power;

[0058] In the topology optimization module, the following analysis is performed based on the equivalent model of the grid-side converter outlet of the optimization system:

[0059]

[0060] in, To optimize the system output current; is the current of the input optimization system; j is the imaginary unit; n is the harmonic number; ω is the angular frequency; k is the bus voltage of the power grid at the sending end; T is the ratio of the converter transformer of the uncontrolled rectifier valve; L is the series filter inductance of the optimization system; C is the filter capacitor of the optimization system; 1∠30° represents the phase angle of the offset;

[0061] Ignoring the harmonic content of the bus voltage, transform the complex frequency of the above formula:

[0062]

[0063] Where G(s) is the transfer function; s is the Laplace complex variable;

[0064] Define the index k n :

[0065]

[0066] Combined, we get:

[0067]

[0068] Among them, k n Indicates the conversion rate of the nth harmonic current after capacitor filtering;

[0069] During the application of the optimization system, the control strategies of AC voltage, active power, reactive power and frequency at the sending end during the stable transmission stage of wind power are as follows:

[0070] The voltage of the power grid at the sending end is controlled by the wind turbines, and the d-axis voltage reference value of each wind turbine is generated through active power control. Generate the phase θ of each wind turbine through reactive power synchronization control i , combined with U 0q Reactive current reference value generated by the control link To change Q wt Size, so that the system reactive power balance;

[0071] The parameter setting module performs parameter setting on the series filter inductor and the shunt capacitor as follows:

[0072] Calculate the active power and reactive power in the AC system as follows:

[0073]

[0074] Among them, P and Q are the active power and reactive power of the AC system respectively; U PCC is the AC bus voltage amplitude; I dc is direct current;

[0075] According to actual engineering needs, set |k n |=m% and the values ​​of active power P and reactive power Q to be adjusted, where m is the setting parameter; and at the same time, the optimal variation range of LC is set.

[0076] A computer readable medium stores computer program instructions, which can be executed by a processor to implement the method as described above.

[0077] Compared with the prior art, the present invention provides an optimization system and method for a grid-type fan connected to an uncontrolled rectifier and delivery scenario, which has the following beneficial effects:

[0078] The present invention reduces the capacitance of the compensation capacitor, saves costs, reduces the floor space of reactive power compensation facilities, and saves the construction cost of the compensation device by combining the PV control algorithm and Qf control algorithm of the grid-connected wind turbine with uncontrolled rectifier transmission with the optimization system; and can significantly reduce the harmonic voltage and harmonic capacitance on the valve-side line of the converter transformer, which has great application value in practical engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 This is a schematic diagram of the optimization system structure mentioned in Example 1 of the present invention;

[0080] Figure 2 This is an equivalent circuit model diagram of the wind turbine grid-side converter outlet mentioned in Embodiment 1 of the present invention;

[0081] Figure 3 This is a control block diagram of the wind turbine side and grid side converters mentioned in Embodiment 1 of the present invention;

[0082] Figure 4 This is a comparison diagram of the system AC side voltage waveform simulation mentioned in Example 1 of the present invention;

[0083] Figure 5This is a simulation comparison diagram of reactive power required by the system mentioned in Example 1 of the present invention;

[0084] Figure 6 This is a schematic diagram of the device mentioned in Example 2 of the present invention. DETAILED DESCRIPTION

[0085] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0086] The present invention reduces the capacitance of the compensation capacitor, saves costs, reduces the floor space of reactive power compensation facilities, and saves the construction cost of the compensation device by combining the PV control algorithm and Qf control algorithm of the grid-type wind turbine connected to uncontrolled rectifier power transmission with the optimization system; and can significantly reduce the harmonic voltage and harmonic capacitance on the valve-side line of the converter transformer, which has great application value for practical engineering. Specifically, it includes the following contents.

[0087] Embodiment 1:

[0088] See also Figure 1-5 The present invention is used for an optimization system and method in a scenario where a grid-type wind turbine is connected to an uncontrolled rectifier and sent out. The improved parallel capacitor phase-commutated converter is applied to a scenario where a grid-type wind turbine is connected to an uncontrolled rectifier and sent out to form an optimization system. The optimization system includes: the industrial frequency AC power output by a large-scale wind farm is collected to the boosting platform of each field area, and the wind turbines in each wind farm are boosted by a boost transformer and connected to the nearest DRU through a short-distance industrial frequency cable. The electric energy is rectified and sent out by the sending-end converter, that is, the sending-end DRU, and is transmitted to the receiving-end modular multi-level converter, that is, the receiving-end MMC, through a long-distance DC cable, and is inverter-incorporated into the receiving-end industrial frequency AC power grid. The sending-end distributed commutation platforms 1 and 2 are connected by a short-distance DC connection cable. The sending-end DRU adopts a 12-pulse DRU, which is formed by cascading two 6-pulse DRUs, and phase-shifting is performed through a converter transformer. The AC side inlet of each DRU converter valve is first connected to the converter transformer T, then connected to the series filter inductor L0, and then connected to the AC bus after the filter capacitor C is connected in parallel; the DC side is connected in series with the smoothing reactor L dc .

[0089] Reference Figure 2 The equivalent circuit model of the wind turbine grid-side converter outlet is constructed, and the active power expression of the wind turbine outlet is obtained as follows:

[0090]

[0091] Where: P wt is the active power generated by the fan; V dciis the DC side outlet voltage of the uncontrolled rectifier valve; N is the number of twelve-pulse uncontrolled rectifier bridges in series; E is the AC side voltage of the uncontrolled rectifier valve; X T is the impedance of the converter transformer.

[0092] The expression of reactive power and frequency in this scenario is:

[0093]

[0094] Where: Q wt V is the reactive power generated by the fan; PCC is the grid voltage at the sending end; V dcr is the DC side voltage of the receiving-end converter; μ is the commutation overlap angle of the uncontrolled rectifier bridge; C0 is the capacitance of the equivalent reactive power compensation device;

[0095] At the same time, the sending-end grid voltage is also theoretically analyzed, and the expression is obtained as follows:

[0096]

[0097] Where: T dr R is the transformer ratio of the uncontrolled rectifier valve converter; dc is the equivalent resistance of the DC transmission line;

[0098] From the above analysis, we can get that the active power generated by the wind turbine is highly correlated with the voltage of the power grid at the sending end. In addition, the DC voltage at the receiving end has a clamping effect on the voltage of the power grid at the sending end, making the voltage change of the power grid at the sending end smaller. When the voltage amplitude is fixed, the frequency at the outlet of the wind turbine is related to the reactive power, so the reactive power can be used for frequency regulation.

[0099] Reference Figure 3 ,In the stage of stable wind power transmission, the control strategies of AC voltage, active power, reactive power and frequency at the sending end are as follows:

[0100] The voltage of the power grid at the sending end is controlled by the wind turbines, and the d-axis voltage reference value of each wind turbine can be generated through active power control. The phase θ of each wind turbine can be generated by reactive power synchronous control i , combined with U 0q Reactive current reference value generated by the control link To change Q wt The size makes the system reactive power balanced, thereby maintaining the stability of the AC voltage and frequency at the sending end.

[0101] For further information on the impact of the optimization system on this system, please refer to Figure 2 The grid-side converter outlet equivalent model is used for corresponding analysis:

[0102]

[0103] in, To optimize the system output current; is the current of the input optimization system; j is the imaginary unit; n is the harmonic number; ω is the angular frequency; k is the bus voltage of the power grid at the sending end; T is the ratio of the converter transformer of the uncontrolled rectifier valve; L is the series filter inductance of the optimization system; C is the filter capacitor of the optimization system; 1∠30° represents the phase angle of the offset;

[0104] Ignoring the harmonic content of the bus voltage, transform the complex frequency of the above formula:

[0105]

[0106] Where G(s) is the transfer function; s is the Laplace complex variable; refer to Figure 4 In the figure, the voltage waveform before the optimization system is applied is relatively rough. The voltage waveform after the optimization system is applied is similar to that in the business area and is smoother. It can be found that the optimization system has a significant effect on filtering out the harmonics of the corresponding wave.

[0107] Define the index k n , used to represent the nth harmonic current conversion rate after capacitor filtering, is defined as:

[0108]

[0109] The combination can get:

[0110]

[0111] As mentioned above, the harmonic phasor is approximately zero and can be ignored, so:

[0112]

[0113] |k n The smaller | is, the smaller the amplitude of the nth harmonic is. Since 12-pulse uncontrolled rectifier transmission is used in this scenario, the harmonic order in the AC system is 12k±1, and the lowest order is 11th, so |k 11 |It is an important indicator for evaluating the harmonic content of the system.

[0114] In order to adjust and optimize the filter inductance and filter capacitance of the system, it is necessary to obtain the calculation formula of active power and reactive power in the AC system:

[0115]

[0116] Among them, P and Q are the active power and reactive power of the AC system respectively; U PCCis the AC bus voltage amplitude; I dc is a direct current.

[0117] The specific parameter design method is as follows: (1) To ensure good AC and DC harmonic characteristics, let |k n =m%, can be set according to actual engineering needs. n |, for example, in this scenario, n can be set to 11 and m can be set to 1. (2) According to the actual needs of the project, the active power P and reactive power Q that need to be adjusted are designed, for example, P is 1000MW and Q is 0MVar. (3) Considering the volume and cost, LC should not be too large. Among them, (1) and (2) are the main constraints, and (3) is the secondary constraint. The main constraints need to be met first, and under this premise, the secondary constraints should be met as much as possible to improve system performance.

[0118] Comparing the size of the adjusted parallel capacitor and the size of the direct parallel capacitor, as mentioned above, the system parameters are P = 1000MW, Q = 0MVar, DC voltage is 500kV, and DC current is 2kA. The calculated capacitance value required in the optimized system is 13.344μF. If the capacitor is directly connected in parallel, referring to the relationship between the active power and reactive power of the uncontrolled rectifier, it can be calculated that the capacitance value of the capacitor required in parallel is 25.272μF. It can be known that the capacitance in this system is smaller than the direct parallel capacitor, which can save costs.

[0119] Finally, the power operation characteristics of the grid-type wind turbine in the optimization system application under the scenario of uncontrolled rectification and transmission are analyzed. Figure 5 ,As can be seen from the figure, after applying the optimization system in this scenario, the ,power operation characteristics are greatly improved, which is conducive to the ,stable operation of the system.

[0120] Therefore, a grid-type control technology for connecting new energy to uncontrolled rectifier converters is proposed. Its topology is that multiple grid-type wind turbines are collected on the AC bus and sent out through uncontrolled rectifier bridges. The receiving end adopts MMC inverter grid connection. Compared with existing projects, it can significantly reduce the volume and weight of the sending end converter station, occupy a small area, save a lot of costs, and is expected to become a better choice for the transmission of new energy.

[0121] Embodiment 2:

[0122] In addition, the embodiment of the present application also provides an optimization device for a grid-type fan connected to an uncontrolled rectifier and delivery scenario, the structure of which is as follows: Figure 6 As shown, the device includes: a scenario analysis module 1, a topology optimization module 2, a parameter setting module 3 and a performance evaluation module 4, wherein the device executes the method described in Example 1.

[0123] Embodiment 3:

[0124] The methods and / or embodiments in the embodiments of the present application may be implemented as computer software programs. For example, the embodiments of the present disclosure include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes program code for executing the method shown in the flowchart. When the computer program is executed by the processing unit, the above functions defined in the method of the present application are executed.

[0125] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An optimization system for grid-type fans connected to uncontrolled rectification and delivery scenarios, characterized in that: The optimization system includes: an improved parallel capacitor commutation converter and a system used in the scenario of grid-type wind turbine connected to uncontrolled rectification and transmission, wherein the improved parallel capacitor commutation converter includes a converter transformer, a filter inductor, a parallel capacitor, and a converter; the system used in the scenario of grid-type wind turbine connected to uncontrolled rectification and transmission includes a collection system, which is used to collect wind turbines in various wind farms; The improved parallel capacitor commutation converter is applied to the diode rectifier converter station DRU. The topological connection of the system applied to the scenario of the DRU converter station and the grid-type wind turbine connected to the uncontrolled rectifier and transmission is as follows: The wind turbines in each wind farm are collected to the sending-end collection system through their respective converters and short-distance AC cables. After being stepped up by the step-up transformers, the wind turbines in each wind farm are connected to the nearest sending-end DRU converter station through short-distance cables, and after being rectified by the converter, they are transmitted to the receiving-end modular multi-level converter through long-distance DC cables, and then are inverterized and connected to the industrial frequency AC receiving-end power grid; wherein the sending-end DRU converter stations are connected to each other through short-distance DC connection cables; the collected AC bus first passes through the converter transformer, and then through the series filter inductor and shunt capacitor, and is connected to the AC inlet of the converter, and a smoothing reactor is also connected in series on the DC side; the sending-end DRU converter station is cascaded by m 12-pulse DRUs, wherein each bridge arm of the DRU is composed of a number of diodes connected in series.

2. An optimization system for grid-type wind turbines connected to uncontrolled rectification and delivery scenarios implemented based on the system described in claim 1, characterized in that: The operating frequency of the collection system is 50 Hz. The grid-type fan adopts process control, namely PV control and droop control, namely Qf control.

3. An optimization method for a grid-type wind turbine connected to an uncontrolled rectifier and output scenario implemented by the system of claim 1, characterized in that: The steps include: The power operation characteristics of the system used in the scenario of the grid-type wind turbine connected to uncontrolled rectification and transmission are analyzed, and it is found that there is a correlation between active power and the voltage of the sending-end system, and there is a correlation between reactive power and frequency, and there is a gap in reactive power. The reactive power gap in the scenario of the grid-type wind turbine connected to uncontrolled rectification and transmission is filled by the optimization system; the circuit analysis of the optimization system is performed to obtain the reactive compensation expression of the optimization system, and the parameters of the series filter inductor and the parallel capacitor are adjusted according to the reactive compensation expression; Then the performance of the optimized system after parameter adjustment is evaluated.

4. The optimization method for the grid-type wind turbine connected to uncontrolled rectification and delivery scenario according to claim 3 is characterized in that: In the system used in the scenario of grid-connected wind turbines connected to uncontrolled rectifiers, an equivalent circuit model of the wind turbine grid-side converter outlet is built to obtain the active power and voltage expressions of the wind turbine outlet as follows: Where: P wt is the active power generated by the fan; V dci is the DC side outlet voltage of the uncontrolled rectifier valve; N is the number of twelve-pulse uncontrolled rectifier bridges in series; E is the AC side voltage of the uncontrolled rectifier valve; X T is the impedance of the converter transformer; The expression of reactive power and frequency at the outlet of wind turbine is: Where: Q wt V is the reactive power generated by the fan; PCC is the grid voltage at the sending end; V dcr is the DC side voltage of the receiving-end converter; μ is the commutation overlap angle of the uncontrolled rectifier bridge; C0 is the capacitance of the equivalent reactive power compensation device; By analyzing the voltage of the sending-end grid, the expression is: Where: T dr is the ratio of the converter transformer without controlled rectifier valve; R dc is the equivalent resistance of the DC transmission line; The analysis shows that there is a correlation between the active power generated by the wind turbine and the voltage of the sending-end grid; and the DC voltage at the receiving end has a clamping effect on the voltage of the sending-end grid, limiting the amplitude of the voltage change of the sending-end grid; when the voltage amplitude is fixed, there is a correlation between the frequency at the outlet of the wind turbine and the reactive power, so the wind turbine achieves frequency synchronization through reactive power synchronization control, and achieves output voltage stability of the sending-end wind farm by controlling the active power.

5. The optimization method for the scenario of grid-type wind turbines with uncontrolled rectification and delivery according to claim 4 is characterized in that: The following analysis is performed based on the equivalent model of the grid-side converter outlet of the optimization system: in, To optimize the system output current; is the current of the input optimization system; j is the imaginary unit; n is the harmonic number; ω is the angular frequency; k is the bus voltage of the power grid at the sending end; T is the ratio of the converter transformer of the uncontrolled rectifier valve; L is the series filter inductance of the optimization system; C is the filter capacitor of the optimization system; 1∠30° represents the phase angle of the offset; Ignoring the harmonic content of the bus voltage, transform the complex frequency of the above formula: Where G(s) is the transfer function; s is the Laplace complex variable; Define the index k n : Combined, we get: Among them, k n Indicates the conversion rate of the nth harmonic current after capacitor filtering.

6. The optimization method for the scenario of grid-type wind turbines with uncontrolled rectification and delivery according to claim 5 is characterized in that: During the application of the optimization system, the control strategies of AC voltage, active power, reactive power and frequency at the sending end during the stable transmission stage of wind power are as follows: The voltage of the power grid at the sending end is controlled by the wind turbines, and the d-axis voltage reference value of each wind turbine is generated through active power control. Generate the phase θ of each wind turbine through reactive power synchronization control i , combined with U 0q Reactive current reference value generated by the control link To change Q wt size so that the system reactive power is balanced.

7. The optimization method for the scenario of grid-type wind turbines with uncontrolled rectification and delivery according to claim 6 is characterized in that: The parameters of the series filter inductor and the shunt capacitor are specifically set as follows: Calculate the active power and reactive power in the AC system as follows: Among them, P and Q are the active power and reactive power of the AC system respectively; U PCC is the AC bus voltage amplitude; I dc is direct current; According to actual engineering needs, set |k n |=m% and the values ​​of active power P and reactive power Q to be adjusted, where m is the setting parameter; and at the same time, the optimal variation range of LC is set.

8. An optimization device for a grid-type fan connected to an uncontrolled rectifier and output scenario corresponding to the method described in any one of claims 3 to 7, characterized in that: include: Scenario analysis module (1): used to analyze the power operation characteristics of the grid-connected wind turbine connected to the uncontrolled rectifier transmission scenario, and obtain that there is a correlation between active power and the voltage of the sending end system, there is a correlation between reactive power and frequency, and there is a gap in reactive power; Topology optimization module (2): used to perform topology optimization through the optimization system to fill the reactive power gap in the scenario where the grid-type wind turbine is connected to an uncontrolled rectifier and outputs power, and also to perform circuit analysis on the optimization system to obtain a reactive power compensation expression for the system; Parameter setting module (3): used for setting the parameters of the series filter inductor and the shunt capacitor in the system according to the reactive power compensation expression; Performance evaluation module (4): used to evaluate the performance of the optimization system after parameter adjustment.

9. The optimization device for grid-type fans connected to uncontrolled rectification and delivery scenarios according to claim 8 is characterized in that: In the scenario analysis module (1), an equivalent circuit model of the wind turbine grid-side converter outlet is built for the system used in the scenario of grid-connected wind turbines connected to uncontrolled rectifiers and transmission, and the active power and voltage expressions at the wind turbine outlet are obtained as follows: Where: P wt is the active power generated by the fan; V dci is the DC side outlet voltage of the uncontrolled rectifier valve; N is the number of twelve-pulse uncontrolled rectifier bridges in series; E is the AC side voltage of the uncontrolled rectifier valve; X T is the impedance of the converter transformer; The expression of reactive power and frequency at the outlet of wind turbine is: Where: Q wt V is the reactive power generated by the fan; PCC is the grid voltage at the sending end; V dcr is the DC side voltage of the receiving-end converter; μ is the commutation overlap angle of the uncontrolled rectifier bridge; C0 is the capacitance of the equivalent reactive power compensation device; By analyzing the voltage of the sending-end grid, the expression is: Where: T dr is the ratio of the converter transformer without controlled rectifier valve; R dc is the equivalent resistance of the DC transmission line; The analysis shows that there is a correlation between the active power generated by the wind turbine and the voltage of the power grid at the sending end; and the DC voltage at the receiving end has a clamping effect on the voltage of the power grid at the sending end, limiting the voltage variation of the power grid at the sending end; when the voltage amplitude is fixed, there is a correlation between the frequency and reactive power at the outlet of the wind turbine, so the wind turbine achieves frequency synchronization through reactive power synchronization control, and achieves output voltage stability of the wind farm at the sending end by controlling active power; In the topology optimization module (2), the following analysis is performed based on the equivalent model of the grid-side converter outlet of the optimization system: in, To optimize the system output current; is the current of the input optimization system; j is the imaginary unit; n is the harmonic number; ω is the angular frequency; k is the bus voltage of the power grid at the sending end; T is the ratio of the converter transformer of the uncontrolled rectifier valve; L is the series filter inductance of the optimization system; C is the filter capacitor of the optimization system; 1∠30° represents the phase angle of the offset; Ignoring the harmonic content of the bus voltage, transform the complex frequency of the above formula: Where G(s) is the transfer function; s is the Laplace complex variable; Define the index k n : Combined, we get: Among them, k n Indicates the conversion rate of the nth harmonic current after capacitor filtering; During the application of the optimization system, the control strategies of AC voltage, active power, reactive power and frequency at the sending end during the stable transmission stage of wind power are as follows: The voltage of the power grid at the sending end is controlled by the wind turbines, and the d-axis voltage reference value of each wind turbine is generated through active power control. Generate the phase θ of each wind turbine through reactive power synchronization control i , combined with U 0q Reactive current reference value generated by the control link To change Q wt Size, so that the system reactive power balance; The parameter setting module (3) performs parameter setting on the series filter inductor and the shunt capacitor as follows: Calculate the active power and reactive power in the AC system as follows: Among them, P and Q are the active power and reactive power of the AC system respectively; U PCC is the AC bus voltage amplitude; I dc is direct current; According to actual engineering needs, set |k n |=m% and the values ​​of active power P and reactive power Q to be adjusted, where m is the setting parameter; and at the same time, the optimal variation range of LC is set.

10. A computer readable medium having computer program instructions stored thereon, wherein the computer program instructions can be executed by a processor to implement the method of claims 3-7.

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